(** Attachments for JSON Feed items.

    An attachment represents an external resource related to a feed item,
    such as audio files for podcasts, video files, or other downloadable content.
    Attachments with identical titles indicate alternate formats of the same resource.

    @see <https://www.jsonfeed.org/version/1.1/> JSON Feed Specification *)


(** The type representing an attachment. *)
type t


(** {1 Construction} *)

(** [create ~url ~mime_type ?title ?size_in_bytes ?duration_in_seconds ()]
    creates an attachment object.

    @param url The location of the attachment (required)
    @param mime_type The MIME type of the attachment, e.g. ["audio/mpeg"] (required)
    @param title The name of the attachment; identical titles indicate alternate formats
                 of the same resource
    @param size_in_bytes The size of the attachment file in bytes
    @param duration_in_seconds The duration of the attachment in seconds (for audio/video)

    {b Examples:}
    {[
      (* Simple attachment *)
      let att = Attachment.create
        ~url:"https://example.com/episode.mp3"
        ~mime_type:"audio/mpeg" ()

      (* Podcast episode with metadata *)
      let att = Attachment.create
        ~url:"https://example.com/episode.mp3"
        ~mime_type:"audio/mpeg"
        ~title:"Episode 42"
        ~size_in_bytes:15_728_640L
        ~duration_in_seconds:1800 ()

      (* Alternate format (same title indicates same content) *)
      let att2 = Attachment.create
        ~url:"https://example.com/episode.aac"
        ~mime_type:"audio/aac"
        ~title:"Episode 42"
        ~size_in_bytes:12_582_912L
        ~duration_in_seconds:1800 ()
    ]} *)
val create :
  url:string ->
  mime_type:string ->
  ?title:string ->
  ?size_in_bytes:int64 ->
  ?duration_in_seconds:int ->
  unit ->
  t


(** {1 Accessors} *)

(** [url t] returns the attachment's URL. *)
val url : t -> string

(** [mime_type t] returns the attachment's MIME type. *)
val mime_type : t -> string

(** [title t] returns the attachment's title, if set. *)
val title : t -> string option

(** [size_in_bytes t] returns the attachment's size in bytes, if set. *)
val size_in_bytes : t -> int64 option

(** [duration_in_seconds t] returns the attachment's duration, if set. *)
val duration_in_seconds : t -> int option


(** {1 Comparison} *)

(** [equal a b] tests equality between two attachments. *)
val equal : t -> t -> bool


(** {1 Pretty Printing} *)

(** [pp ppf t] pretty prints an attachment to the formatter.

    The output is human-readable and suitable for debugging.

    {b Example output:}
    {v episode.mp3 (audio/mpeg, 15.0 MB, 30m0s) v} *)
val pp : Format.formatter -> t -> unit